The present invention relates to a straight-pull breechblock with rotating-boss locking mechanism for repeating weapons, having a breechblock sleeve which is guided in a breechblock housing and carries a bolt handle for the manual to-and-fro motion and in which, by means of a shaft, a breechblock head which bears locking bosses is mounted in a forcibly guided, rotatable manner, and which breechblock sleeve comprises a firing pin which is acted upon by a firing spring, which further serves to generate an angular momentum in order to rotate the breechblock head in the locking position into the locking chamber corresponding to the locking bosses.
For this purpose, the breechblock head, which is continuously acted upon by the firing spring, is guided in spiral grooves and, as a result of the pretension of the firing spring, when the front region of the breechblock housing is reached, is transferred into the locking position by means of a clockwise rotation; compare Steyr repeating weapon model 1895.
However, the consequence of this continuous loading of the breechblock head is that over the entire area of the guideways of the breechblock housing, the right-hand locking boss rests resiliently on the latter, which makes the forwards and backwards motion of the straight-pull breechblock considerably more difficult, quite apart from the wear which occurs in this connection.
The object of the invention is to remedy this by means of a new design of a straight-pull breechblock of the type mentioned in the introduction, which is easier to operate than before without the above-mentioned wear.
Starting from the known straight-pull breechblock, this object is achieved in accordance with the invention as a result of the fact that associated with the breechblock sleeve are forcibly controlled stopping means which block the angular momentum which effects the locking of the breechblock.
According to a further feature of the invention, there is provided as the stopping means which suppress relative movements between the breechblock sleeve and the breechblock head a stopping lever which is acted upon by a spring in the stopping direction and is mounted rotatably on the breechblock sleeve, the one lever arm of which stopping lever has a locking projection corresponding with a locking groove in the shaft of the breechblock head and the other lever arm of which has a control ramp which cooperates with a contact edge of the breechblock bridge, all this in such an arrangement that when the breechblock sleeve and breechblock head are moved into the locking position, the stopping lever, upon reaching the locking position, is, by way of the control ramp, against the action of the spring, brought out of engagement with the locking groove, while in the case of movement out of the locking position, the locking projection of the stopping lever which then becomes free engages resiliently again in the locking groove of the breechblock head.
The relative movements between the breechblock sleeve, which carries the bolt handle, and the breechblock head, are, in accordance with the invention, forced by two spiral grooves arranged opposite each other in the shaft of the breechblock head, with which spiral grooves are associated corresponding stationary groove blocks in the breechblock sleeve.
Moreover, the breechblock sleeve has opposing guide bosses which cooperate with guide surfaces of the breechblock housing, one of which guide bosses is used as a bearing for the stopping lever.
Advantageously, the shaft of the breechblock head is provided, at the rear end, with a firing-spring collar screw, which serves as an abutment for the firing spring and by way of which the firing spring is operatively connected to the breechblock head.
Further features of the invention emerge from the subclaims.
As a result of the development in accordance with the invention of the straight-pull breechblock, the considerable angular momentum on the breechblock head is blocked until the locking bosses of the said breechblock head have gone into the region of the locking chamber. In this way, when the breechblock is moved manually forwards and backwards by means of the bolt handle, the resilient resting of the right-hand locking boss of the breechblock head on the respectively associated guideway in the breechblock housing is dispensed with, something which substantially facilitates operation. The mass of the breechblock sleeve that is to be moved by way of the bolt handle is increased only slightly by the stopping lever, and therefore has a negligible effect on the operating convenience. The wear on the breechblock portions is likewise reduced, which has a favourable effect on the reliable locking of the breechblock head.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are intended solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.